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Discussion Starter · #1 ·
I have been spending the past few weekends re-wiring my CJ-7. Today I decided to do the alternator the right way (using the teamrush method I saved awhile ago).
Before it was hooked up this way:
#1 wire to a switched 12V. No light or resistor.
#2 wire to battery side of the started solenoid
Charge wire (no fuseable link) to battery side of starter solenoid.
No ground (besides bracket)

Now it is wired this way:
#1 wire running through idiot light to a switched 12V .
#2 wire to switched 12V
10 Ga Charge wire to battery side of starter solenoid through 12Ga fuseable link.
8Ga ground wire from the alt case directly to battery -.

My idiot light does not turn off....does this mean the voltage regulator in the alternator is shot? Possibly because of the way it was wired before? Or did I wire something wrong? It still seems to be charging the system and staying between 12 and 13 volts.







'79 CJ-7
 

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The #1 terminal could use a 194 bulb or 1 watt 100 ohm resistor with 12 volts coming from the "ON" position of the ignition switch. The #1 terminal of the AC Delco alternator will act like a ground until the alternator starts to spin. Once the alternator starts spinning the ground goes away and the light should go out. I think maybe something is wired wrong, or the alternator is bad.

The #2 terminal needs 12 volts from the battery all the time. The #2 terminal should not be switched with 12 volts. I recommend a 10 gauge or 12 gauge wire for the #2 terminal. It's OK to connect the #2 wire to the "BAT" terminal on the back of the alternator.

Your other two wires seem fine.
dave

 

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*ChrisM* said,
*Now it is wired this way:
#1 wire running through idiot light to a switched 12V .
#2 wire to switched 12V
10 Ga Charge wire to battery side of starter solenoid through 12Ga fuseable link.
8Ga ground wire from the alt case directly to battery -.*

Good job on grounding the alternator!!
#2 Could also go to the hot side of the horn relay, that is a full load terminal, and it's in the engine bay...
Sounds like you have everything wired alright...

Did you use a bulb socket that controls the ground...?
If it grounds through the frame of the light, you will have a light on all the time...

If the bulb you used doesn't have enough resistance the light wont work.
Hit Radio Shack for a 150 Ohm, 1 Watt Resistor, and add it to the light line.
If the light still doesn't go out, take the alternator to an Auto Jerks store and have them test it. The test is usually free...
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*My idiot light does not turn off....does this mean the voltage regulator in the alternator is shot? Possibly because of the way it was wired before? *

Very possible.
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*Or did I wire something wrong?*

Doesn't seem like it... Try connecting the #2 wire to the battery before you start it.
If the light goes out, you found the problem...
Also try the resistor in the #1 wire line....
Also don't forget the Auto Jerks test...
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*It still seems to be charging the system and staying between 12 and 13 volts.*

It can still be charging and not be working right. I've seen some pretty strange things down through the years...
Some times you have to rev the engine up once to get them to go out. When that happens, you have corroded wiring, or the regulator is on it's last legs...

Hope this helps, Aaron...




If Chris Columbus "Discovered" America (with 25 million already here), Can I Go "Discover" Florida?
 

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Discussion Starter · #4 ·
And the verdict is....bad alternator. Had it tested at napa last night. No problem this give me the opportunity to upgrade to the 94a version.
Just in case anyone wanted to know, the alt from a '91 Grand Wagoneer is 94a and a direct bolt on replacement (for AMC v8's anyway).

As for the #2 wire....Dave says directly to the battery because it needs 12V all the time, and TR says to a switched 12V...Which one is it guys?

Thanks,
Chris

'79 CJ-7
 

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Just take a volt meter to a GM vehicle with a 10Si and check the #2 wire, I'll bet a cold beer on a hot summer night that the #2 wire will be HOT all the time.
dave

 

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Dave's way will work, and that is the way a lot of older factory systems with the Delco alternator were wired.

Dave is VERY good at what he does, and I don't want to upset him, but I disagree with him on this one. (nothing personal, just a disagreement on the small details)
I'm positive he has very well though out reasons for doing things the way he does.

He always has very good reasoning for what he says, and when he is in error, it's to the conservative side, where nothing blows up or catches fire!!

(He isn't just spouting off what he's heard somewhere without understanding how the system works, he knows his stuff!!)
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This is just the way I do it, and the reason WHY I do it that way...
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The #2 wire is the 'Sensor' wire for the voltage regulator, and it also supplies the power to energize the alternator so it will put out.
I prefer to connect that wire to a power source that is after the normal load of the vehicle, that way the alternator's regulator has a more accurate idea of what the vehicle loads really are.

If you run it straight back to the battery, all the alternator gets input from is the voltage at the positive terminal.
By the time you add up old, corroded or dirty connections, all of the parasitic loads, all of the loads of added on do-dads like extra lights and radios, bad grounds, ect, 12.8 volts and nearly zero amperage (after catching up from initial start up) at the battery doesn't mean much on vehicles with large drains after the battery...
The battery voltage may be 12.8 or slightly higher, but it may take 14.5 volts and considerable amperage to get enough current through to some of the more out of the way goodies...
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Hooking the #2 wire up post parasitic load will also sense when the voltage drops in the system. Say when big lights or a winch on a separate circuit are used, and put a drain on the system...
It will tell when the system voltage drops, and crank up the alternator.

I especially like hooking up the #2 wire post fuse box if the vehicle has a computer of one sort or another.
It helps keep the current steady at the fuse box for the computer...
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The battery also acts like a giant capacitor to buffer the supply vs. demand.
Have you ever seen a vehicle where you pull the headlights on and turn something like the heater on and the headlights dim?
That is the battery working as a buffer. The lights will stay dim until the alternator besides the battery is in trouble, and kicks up the current some.
If the #2 wire were connected to a post load source, instead of a pre load source, as soon as you turn anything on the current output goes up, and if the lights dim, it will only be for a second.
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The horn relay supply is a good example of a place to get input after all of the internal loads of your system.
It's a heavy feed wire, after the fuse box and internal loads, it's on the tail end of the system. If you connect here, and get 12.8 volts or better here, you entire system is correctly supplied.

Most factory wiring harnesses are the absolute minimum they can get away with, so are ignition switches.
Anytime you add anything to the fuse box, you are adding to an already stressed system, same with the ignition switch.
The Horn Relay Supply is usually a fair wire gauge size, so I like to run the #2 there on stock vehicles. It's usually in the engine bay, and handy too.

On custom street rods, the fuse blocks we use have power connection terminals on both ends. We run the power 'IN' on one end, and take the #2 wire off of the other end. That gives us a good post load source that still supplies plenty of current for operating the alternator.
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WHY I SAID SWITCHED FOR #2...
This very question has been asked before.
You have a copy of instructions for a guy that said his Jeep didn't get driven very often, and his battery kept going dead.
I said to run that connection through a switched source because that wire is hot all the time. If something was wrong in the alternator, that was one of the sources of the drain.
By going through the switch, it was cut off when he shut the key off automatically, no need to flip a switch, or to disconnect the battery.

There is a fairly large load on the #2 wire from time to time, so 12 Ga wire is pretty well a must...
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You would win a cold been on most stock vehicles, but who here has a 'Stock' jeep here???
The Horn relay will be a 'HOT' source also...


Hope this helps clear up the confusion,
Aaron.



If Chris Columbus "Discovered" America (with 25 million already here), Can I Go "Discover" Florida?
 
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